{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT2028-4BB40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT2028-4BB40","canonicalUrl":"https://aoctrl.com/siemens/3RT2028-4BB40","factsUrl":"https://aoctrl.com/api/mcp/products/3RT2028-4BB40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS Size S0 power contactor, 3RT2028-4BB40, 480 V AC-3 34 A, 600 V AC-3 27 A, screw and snap-on 35 mm DIN rail, 24 V DC coil.","salesMarkdown":"## Siemens 3RT2028-4BB40 SIRIUS Power Contactor — Size S0, 480V 34A The Siemens SIRIUS 3RT2028-4BB40 is a Size S0 power contactor rated for 34 A at 480 V and 27 A at 600 V in AC-3 duty, meaning it handles motor switching loads up to those currents without welding the main contacts. The S0 frame takes 45 mm width on the rail, with 85 mm height and 107 mm depth — factor that into your gland-plate layout and enclosure fill. ## Switching Frequency and Duty Cycles This contactor is rated for 1 000 switching cycles per hour at AC-1 (resistive loads), 750 cycles/h at AC-2 and AC-3 (motor starting/running), and 250 cycles/h at AC-4 (plugging/inching). The AC-3e rating also sits at 750 cycles/h. If your application involves frequent jogging or reversing, the AC-4 limit is the one that governs contact life — don't exceed 250 cycles/h in that duty. ## DC Switching Capability and Coil Details The magnet coil uses a ring cable lug connection — plan for ring terminals, not fork or pin. DC switching ratings are provided across multiple voltages: 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, 3 A at 400 V, 0.6 A at 440 V, 2 A at 500 V. These are the DC-1 or DC-13 ratings (not explicitly stated, but typical for this class) — if you're switching DC motor or solenoid loads, use the voltage-specific value, not the AC rating. ## Environmental and Mounting Clearances Keep those clearances for airflow and arc flash containment — especially the 10 mm forward clearance for the arc chute.","metaTitle":"Siemens 3RT2028-4BB40 SIRIUS Power Contactor, 480V 34A, Size","metaDescription":"Siemens SIRIUS 3RT2028-4BB40 power contactor, Size S0, 480V AC-3 rated at 34A, 600V at 27A. DC switching ratings included. Screw and snap-on 35mm DIN rail mounting. Available to or","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"107 mm","Width":"45 mm","at DC":"15 ... 18 ms","title":"3RT2028-4BB40","Height":"85 mm","Upwards":"10 mm","Forwards":"10 mm","Downwards":"10 mm","Arcing Time":"10 ... 10 ms","At The Side":"6 mm","Rated Value":"24 V","description":"power contactor, AC-3e/AC-3, 38 A, 18.5 kW / 400 V, 3-pole, 24 V DC, auxiliary contacts: 1 NO + 1 NC, ring cable lug connection, size: S0","Initial Value":"0.8","During Storage":"-55 ... +80 °C","Of Magnet Coil":"Ring cable lug connection","at AC-1 maximum":"1 000 1/h","at AC-2 maximum":"750 1/h","at AC-3 maximum":"750 1/h","at AC-4 maximum":"250 1/h","lifecycle_stage":"current","Auxiliary Switch":"Yes","During Operation":"-25 ... +60 °C","Fastening Method":"screw and snap-on mounting onto 35 mm DIN rail according to DIN EN 60715","Full-Scale Value":"1.1","at AC-3e maximum":"750 1/h","Mounting Position":"+/-180° rotation possible on vertical mounting surface; can be tilted forward and backward by +/- 22.5° on vertical mounting surface","Size Of Contactor":"S0","Product Brand Name":"SIRIUS","Product Designation":"Power contactor","at 24 V rated value":"10 A","at 48 V rated value":"2 A","at 60 V rated value":"2 A","Of Contactor Typical":"10 000 000","at 110 V rated value":"1 A","at 125 V rated value":"0.9 A","at 220 V rated value":"0.3 A","at 230 V rated value":"5 hp","at 400 V rated value":"3 A","at 440 V rated value":"0.6 A","at 480 V rated value":"34 A","at 500 V rated value":"2 A","at 600 V rated value":"27 A","at 690 V rated value":"1 A","Side-By-Side Mounting":"Yes","For Main Current Circuit":"Ring cable lug connection","at 110/120 V rated value":"3 hp","at 200/208 V rated value":"10 hp","at 220/230 V rated value":"10 hp","at 460/480 V rated value":"25 hp","at 575/600 V rated value":"25 hp","Relative Humidity Minimum":"10 %","Of Main Circuit Rated Value":"6 kV","at AC-3 rated value maximum":"690 V","at AC in hot operating state":"9.6 W","at AC-2 at 400 V rated value":"18.5 kW","at AC-3e rated value maximum":"690 V","at AC-4 at 400 V rated value":"22 A","safety-related switching OFF":"Yes","Substance Prohibitance (Date)":"10/01/2009","Of Auxiliary Circuit Rated Value":"6 kV","at AC-5a up to 690 V rated value":"44 A","at AC-5b up to 400 V rated value":"31.5 A","For Auxiliary And Control Circuit":"ring terminal lug connection","Function Module For Communication":"No","With Type Of Assignment 2 Required":"gG: 50A (690V,100kA), aM: 25A (690V, 100kA), BS88: 50A (415V, 80kA)","Without Load Current Share Typical":"5.9 W","closing power of magnet coil at DC":"5.9 W","holding power of magnet coil at DC":"5.9 W","At Contactor For Auxiliary Contacts":"Ring cable lug connection","With Type Of Coordination 1 Required":"gG: 125A (690V,100kA), aM: 50A (690V,100kA), BS88: 125A (415V,80kA)","operational current at AC-12 maximum":"10 A","at AC in hot operating state per pole":"3.2 W","number of NO contacts for main contacts":"3","reference code according to IEC 81346-2":"Q","Number Of Poles For Main Current Circuit":"3","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","mirror contact according to IEC 60947-4-1":"Yes","with low demand rate according to SN 31920":"40 %","with high demand rate according to SN 31920":"73 %","Type Of Voltage Of The Control Supply Voltage":"DC","Limited To 1 S Switching At Zero Current Maximum":"593 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 5 S Switching At Zero Current Maximum":"341 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 10 S Switching At Zero Current Maximum":"260 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 30 S Switching At Zero Current Maximum":"199 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 60 S Switching At Zero Current Maximum":"162 A; Use minimum cross-section acc. to AC-1 rated value","contact rating of auxiliary contacts according to UL":"A600 / P600","Of Main Circuit With Degree Of Pollution 3 Rated Value":"690 V","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Of The Contactor With Added Auxiliary Switch Block Typical":"10 000 000","Of Auxiliary Circuit With Degree Of Pollution 3 Rated Value":"690 V","For Short-Circuit Protection Of The Auxiliary Switch Required":"gG: 10 A (500 V, 1 kA)","minimum cross-section in main circuit at maximum AC-1 rated value":"10 mm²","number of NC contacts for auxiliary contacts instantaneous contact":"1","number of NO contacts for auxiliary contacts instantaneous contact":"1","Of The Contactor With Added Electronically Optimized Auxiliary Switch Block Typical":"5 000 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/bbfe1d9ef615a9b7096c27e1bf46998a.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=409648&mlfb=3RT2028-4BB40"},"ai":{"faq":[{"question":"What are the key ratings for the 3RT2028-4BB40?","answer":"It is a Size S0 power contactor rated 34 A at 480 V AC-3 and 27 A at 600 V AC-3, with a 24 V DC coil. DC switching ratings include 10 A at 24 V, 2 A at 48 V, and 1 A at 110 V."},{"question":"What is the depth of the 3RT2028-4BB40?","answer":"The depth is 107 mm, with a width of 45 mm and height of 85 mm."},{"question":"Where can I buy the 3RT2028-4BB40 and how is it quoted?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm price and lead time."},{"question":"Will the 3RT2028-4BB40 fit on a 35 mm DIN rail?","answer":"Yes, it uses screw and snap-on mounting onto 35 mm DIN rail per DIN EN 60715, with the S0 frame occupying 45 mm width."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT2028-4BB40","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/3RT2028-4BB40 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}